Knee osteoarthritis

Red Flags

Hot swollen joint with fever — exclude septic arthritis (joint aspiration); empirical antibiotic until ruled out^[1]
Locked knee, sudden inability to extend, or trauma — orthopaedic review for meniscal tear, loose body, or fracture^[1]
Inflammatory arthritis features (early morning stiffness >60 min, multiple small joints, systemic features) — rheumatology workup^[1]
Severe disabling pain refractory to conservative therapy with end-stage radiographic OA — orthopaedic surgical evaluation^[1]

First-line treatment

Interventions

Education, self-management, lifestyle change^[1]
Cornerstone of management; structured patient education, activity modification, joint protection; community programmes (osteoarthritis schools); arthritis self-management courses
Weight reduction (BMI ≥25)^[1]
5–10% weight loss reduces knee pain and improves function; meaningful at any BMI; combined dietary and exercise approach
Structured exercise — strengthening + aerobic^[1]
Quadriceps strengthening, range-of-motion exercises, low-impact aerobic (walking, swimming, cycling), tai chi, yoga; supervised programme initially then home maintenance; equally effective regardless of severity
Bracing, footwear, and orthoses (selected)^[1]
Knee brace for medial OA with varus deformity; appropriate footwear; lateral wedge insoles inconsistent benefit; walking aids for severe disease
Avoid ineffective therapies^[1]
Routine glucosamine and chondroitin not recommended; arthroscopic lavage and debridement no benefit (NICE, AAOS, OARSI); avoid intra-articular hyaluronan as routine (mixed evidence)

First-line drug therapy

Drug	Class	Adult	Paediatric	Notes
Topical NSAID (diclofenac gel, ketoprofen)^[1]	Topical NSAID	Apply 2–4 g to affected knee 3–4× daily	—	First-line topical for knee OA; comparable efficacy to oral NSAID with much lower systemic exposure; preferred in elderly and CKD
Paracetamol^[1]	Analgesic	1 g PO QDS PRN, max 4 g/day	—	Limited efficacy in OA per recent reviews; useful adjunct or when NSAID contraindicated; lowest effective dose
Oral NSAID (naproxen, ibuprofen, celecoxib)^[1]	Cyclooxygenase inhibitor	Naproxen 250–500 mg PO BD; ibuprofen 400 mg PO TDS; celecoxib 200 mg PO daily	—	Lowest effective dose, shortest duration; co-prescribe PPI if GI risk; avoid in CKD G3+, peptic ulcer, severe HF, anticoagulation; selective COX-2 if GI risk
Intra-articular corticosteroid^[1]	Glucocorticoid injection	Methylprednisolone 40 mg or triamcinolone 40 mg intra-articular; max 3–4× per year per joint	—	Useful for moderate-severe pain flare; effect 4–8 weeks; transient post-injection flare; chondrotoxicity with repeated injections
Duloxetine^[1]	SNRI antidepressant	30 mg PO daily, titrate to 60 mg	—	Adjunct for moderate-severe OA pain refractory to first-line; analgesic effect at 4–6 weeks; useful with comorbid depression/chronic pain
Tramadol (selected, short-term)^[1]	Atypical opioid / SNRI	50–100 mg PO every 4–6 h, max 400 mg/day	—	Reserve for moderate-severe pain refractory to first-line; constipation, dizziness, dependence concerns; avoid long-term

Topical NSAID (diclofenac gel, ketoprofen)^[1]

Topical NSAID

Adult: Apply 2–4 g to affected knee 3–4× daily
Paediatric: —

First-line topical for knee OA; comparable efficacy to oral NSAID with much lower systemic exposure; preferred in elderly and CKD

Paracetamol^[1]

Analgesic

Adult: 1 g PO QDS PRN, max 4 g/day
Paediatric: —

Limited efficacy in OA per recent reviews; useful adjunct or when NSAID contraindicated; lowest effective dose

Oral NSAID (naproxen, ibuprofen, celecoxib)^[1]

Cyclooxygenase inhibitor

Adult: Naproxen 250–500 mg PO BD; ibuprofen 400 mg PO TDS; celecoxib 200 mg PO daily
Paediatric: —

Lowest effective dose, shortest duration; co-prescribe PPI if GI risk; avoid in CKD G3+, peptic ulcer, severe HF, anticoagulation; selective COX-2 if GI risk

Intra-articular corticosteroid^[1]

Glucocorticoid injection

Adult: Methylprednisolone 40 mg or triamcinolone 40 mg intra-articular; max 3–4× per year per joint
Paediatric: —

Useful for moderate-severe pain flare; effect 4–8 weeks; transient post-injection flare; chondrotoxicity with repeated injections

Duloxetine^[1]

SNRI antidepressant

Adult: 30 mg PO daily, titrate to 60 mg
Paediatric: —

Adjunct for moderate-severe OA pain refractory to first-line; analgesic effect at 4–6 weeks; useful with comorbid depression/chronic pain

Tramadol (selected, short-term)^[1]

Atypical opioid / SNRI

Adult: 50–100 mg PO every 4–6 h, max 400 mg/day
Paediatric: —

Reserve for moderate-severe pain refractory to first-line; constipation, dizziness, dependence concerns; avoid long-term

Safety-net

Daily quadriceps exercises and weight reduction are the most powerful long-term treatments — combine with simple analgesia^[1]
Avoid prolonged use of oral NSAIDs and opioids — topical NSAIDs are safer for daily use^[1]
Hot swollen joint, fever, sudden inability to bear weight, or red spreading skin — same-day medical review (rule out septic arthritis)^[1]

Referral criteria

Septic arthritis suspicion, locked knee, or significant traumaEmergency orthopaedics^[1]
Severe disabling pain refractory to ≥3 months conservative therapy with end-stage radiographic OAOrthopaedic surgery for arthroplasty (TKR or UKA) or osteotomy in selected younger active^[1]
Inflammatory features or suspected non-OA aetiology (rheumatoid, gout, psoriatic, septic)Rheumatology^[1]
Ongoing functional impairment despite optimal medical managementMultidisciplinary OA clinic with physiotherapy, OT, weight management^[1]

Clinical summary

Diagnosis, lifestyle, pharmacological and surgical management of knee osteoarthritis in adults.

References

1.MoHFW Standard Treatment Guideline — Osteoarthritis Knee (2021); OARSI Treatment Guidelines for OA of Knee, Hip and Polyarticular OA (2019); ACR/AF Guideline for the Management of OA (2019) (2021)